Physicists report a new type of genetically encoded fluorescent probe

 A research team from the Physics Department at King’s College London, the University of California, Berkeley, and Santa Clara University have published a report in the Proceedings of the National Academy of Sciences (USA), on a new type of genetically encoded fluorescent protein that is found in a bioluminescent symbiont that populates the light organ of the ponyfish.

The lumazine binding protein (or LUMP) is distinct from the more famous and widely used cyan fluorescent protein (CFP) in having 67% of the mass and a fluorescence lifetime of almost 14 ns, the longest of any encoded protein. The small mass and long lifetime of LUMP allow it to function as a universal sensor of protein hydrodynamics, which is accomplished simply by measuring the anisotropy of LUMP fluorescence. 

The team reports that by appending specific amino acid sequences to LUMP, one can detect and quantify an interaction of a LUMP sensor with almost any protein. The determination of binding is simply based on whether the LUMP-fusion protein tumbles rapidly, i.e. unbound, or slowly i.e. complexed. “Since these measurements can be made within individual cells, it now becomes possible to carry out rapid, quantitative and proteome-wide analyses of specific protein interactions, or to screen for drugs having a designed function to disrupt a specific protein complex in a living cell. 

"Equally noteworthy is that LUMP is optimized for Förster Resonance Energy Transfer (FRET)-based measurements of molecular proximity, e.g. for protein-protein interactions”, Professor Klaus Suhling from the Department of Physics explained. For example, it may provide great improvement on the efficiency of FRET when fused via a thrombin-cleavable peptide to an acceptor protein such as a Venus fluorescent protein.

For more information and to view the publication, visit the PNAS website: http://www.pnas.org/content/early/2015/04/29/1424021112

A. Hoepker, A. Wang, A. Le Marois, K. Suhling, Y. Yan, G. Marriott 'Genetically-encoded sensors for fluorescence anisotropy and Foersterr.'